<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .color{
            color: red;
        }
    </style>
</head>
<body>
    <div id="app">
        <ul>
            <li v-for="(item,index) in list" @click="changeIndex(index)" :class="{ color:index === number }">
                {{index}}-{{item}}
            </li>
        </ul>
    </div>
    <script src="../js/vue.js"></script>
    <script>
        const app = new Vue({
            el:'#app',
            data(){
                return {
                    list:['蜘蛛侠','蝙蝠侠','小猪佩奇','猪猪侠','花园宝宝'],
                    number:null
                }
            },
            methods:{
                changeIndex(i){
                    this.number = i
                }
            }
        })
    </script>
</body>
</html>